Primer Coating Composition for Automotive Laser Pattern Adhesion
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Solution Overview
Problem
The high-temperature annealing process used in coating treatments for automotive exterior parts leads to decreased adhesion between the laser pattern and the coating layer and clear layer, resulting in poor laser processability and clearness of the design.
Innovation Solution
A primer coating composition comprising 20-25 wt% chlorinated polyolefin resin with a weight-average molecular weight of 50,000 to 100,000 g/mol, 2-4 wt% modified polyester, and 75-85 wt% hydrocarbon-based solvent is applied between the printing and clear layers to enhance adhesion and maintain clearness of the laser pattern design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature annealing process is performed to secure clearness of laser pattern design, then clearness of laser pattern is improved, but adhesion between laser pattern and coating layer decreases
Solution Approach 1:
A primer layer is introduced as an intermediary between the coating layer and the laser pattern. This primer layer acts as a mediator that maintains adhesion strength while allowing the high-temperature annealing process to proceed for achieving clear laser pattern design. The primer layer composition (specific resins and solvents) is designed to withstand the annealing temperature while preserving bonding properties.
Solution Approach 2:
The invention changes the chemical composition parameters of the primer layer by selecting specific resins (first and second resins with different Tg values) and solvents. By controlling the glass transition temperatures and chemical structures of these components, the primer layer can endure high-temperature annealing without losing adhesion, thus resolving the contradiction between pattern clearness and bonding strength.
2Manufacturing precision
If high-temperature annealing process is performed to secure clearness of laser pattern design, then clearness of laser pattern is improved, but adhesion between clear layer and coating layer decreases
Solution Approach 1:
The primer layer serves as a protective intermediary between the clear layer and the coating layer during the high-temperature annealing process. It prevents direct thermal damage to the interface between the clear layer and coating layer, thereby maintaining adhesion strength while enabling the annealing process needed for clear laser pattern formation.
Solution Approach 2:
By carefully selecting the glass transition temperatures (Tg) of the resins in the primer layer, the invention creates a thermal buffer zone that protects the clear layer-coating layer interface during annealing. The specific Tg values ensure the primer remains stable at annealing temperatures while preserving the bonding integrity of adjacent layers.
3Ease of manufacture
If conventional coating composition is used, then coating process is simple, but laser processability and clearness of design are poor
Solution Approach 1:
The primer layer uses a composite material system consisting of two different resins and two different solvents with specifically controlled properties. This composite structure enables the coating to achieve both good laser processability and clear pattern design, overcoming the limitations of conventional single-component coating compositions.
Solution Approach 2:
The invention optimizes multiple parameters simultaneously: resin types, their glass transition temperatures, solvent types, and their proportions. These parameter adjustments enhance laser processability and pattern clearness while maintaining a relatively simple coating process, thus resolving the contradiction between manufacturing simplicity and design quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The primer coating composition improves the adhesion between the coating and clear layers, maintaining the clarity and design integrity of the laser pattern while ensuring the durability and water resistance of the automotive coating.
Implementation Method 1
improve adhesion between a coating layer and a clear layer
Implementation Method 2
ensuring the durability and water resistance of the automotive coating
Data Source
AI summary
An embodiment primer coating composition includes 20 to 25 wt % of a chlorinated polyolefin (CPO) resin having a weight-average molecular weight (Mw) of 50,000 to 100,000 g/mol, 2 to 4 wt % of a modified polyester, and 75 to 85 wt % of a hydrocarbon-based solvent. An embodiment coated automotive article includes a printing layer on a base layer, the printing layer including a laser pattern, a primer layer on the printing layer, the primer layer including a primer coating composition including 20 to 25 wt % of a chlorinated polyolefin (CPO) resin having a weight-average molecular weight (Mw) of 50,000 to 100,000 g/mol, 2 to 4 wt % of a modified polyester, and 75 to 85 wt % of a hydrocarbon-based solvent, and a clear layer on the primer layer.